Refrigerating apparatus



Sept. 10, 1940. lLBERT, SR 2,214,298

REFRIGERATING APPARATUS Original Filed May 24, 1.955 2 Sheets-Sheet I p10, 1940- W., GILBERT. S R

REFRIGERATING APPARATUS O'rigina; Filed May 24, 1935 2 Sheets-Sheet 2Patented Sept. 10,1940

UNITED STATES PATENT orFicr:

REFRIGERATING APPARATUS Walter Gilbert, Sn, Johnstown, Pa", assign'or ofone-half to Ernest F. Walker, Johnstown, Pa.

Original application May 24, 1935, Serial No. 23,320. Divided and thisapplication May is,

1937, Serial No. 142,921

2 Claims.

This application is a division of my copending application, SerialNumber 23,320, filed May 24, 1935.

This invention relates to a refrigerating system,

5 and more particularly to a multiple system or system employing aplurality of cooling units operating at different temperatures forsuppyling the required amount of refrigeration, such cooling units beingsupplied with refrigerant from a 10 single compressor condenser unit.

The invention may be utilized for example in an installation having alow temperature cooler to be maintained at a temperature at or below F.and a display counter to be maintained at a temperature above freezingpoint, although it is not limited to systems of this character.

' It is an object 01' the invention to provide improved control meansfor the cooling units for independently regulating the refrigerantsupplied to each cooling unit by means of snap action thermostaticallycontrolled expansion valves or the likeand with additional means forpreventing temperature equalization of the several cooling units by theflow of fluid from one to the other.

35 A further object of the invention is to provide a thermostaticexpansion valve and operating mechanism therefor of improvedconstruction and operating characteristics.

Other objects and advantages of the inven 30 tion will appear from thefollowing description of the embodiments thereof shown in theaccompanying drawings, wherein:

Fig. 1 is a detail view partly in section of one form of the expansionvalve embodying the ina vention;

Fig. 2, a fragmentary sectional view of a modified form of expansionvalve, and

Fig. 3, a diagrammatic view of asystem in which the valves shown inFigs. 1 and 2 may be employed.

Referring to'Fig. 1 of the drawings, an expansion valve embodying theinvention comprises a hollow, generally cylindrical sleeve member Illprovided with an extension or boss I l at the upper 45 end and closed atthe lower end by a cap member l2 secured thereto in any desired manner,as by means of the bolts l3. Bracket members I4 and l5, depending fromthe sleeve member are also clamped thereto by the bolts l3. An insulat50 ing disk I6 is secured to the lower ends of the bracket members I4and I5, as for example by 7 screws l8 threaded into the valve housing H.

An expansible bellows 2,!) is clamped between the cap member I2 and thesleeve I0 and serves 55 to seal the space 2| inside of the sleeve Ill.The

space 2| is in communication through a length of tubing 22 with acapsule 23, the space 2|, tubing 22 and capsule 23 being filled with anexpansible fluid whereby the pressure exerted on the bellows member isdependent upon the temperature to 5 which the capsule 23 is subjected.The capsule 23 is positioned within or adjacent the refrigeratingelement or expansion coil of the refrigerating system in order tocontrol the expansion valve in accordance with the temperature of there- 10 frigerating element, as will be described hereinafter.

A piston 25 having a shank portion 26 surrounding a piston rod 21 isdisposed within the bellows member 20 to be actuated upon an increase inpressure within the sleeve member ID. The movement of the piston '25 isresisted by a coil spring 28 arranged between the shank portion 26 ofthe piston and the threaded shank portion 29 of the thumb screw 3|)threaded into the cap 20 member l2. The piston 25'is biased by thespring 28 in an upward direction, the tension of the spring beingadjustable by means of the thumb screw 30. A reinforcing sleeve 3| maybe provided adjacent the bellows 20 and surrounding the spring 28 toprevent buckling of the bellows member. A pointer 32 cooperating withthe thumb screw permits the same to be calibrated in terms of operatingtemperatures.

A bldck as is secured on the piston rod 21 as 80 for example by means ofclamping nuts 36 threaded on said rod. The block is.notched to formbearings i'orthe knife edge links 31 and 38 forming a toggle link. Theouter ends of the toggle link members 31 and 33 engage bearings in thesupporting arms 39 and 40, the arm lll being piovted at 4| to thebracket member H. The toggle link comprising the members 35, 31 and 38is for the purpose of imparting a snap action to the thermostaticallycontrolled member of the 40 35 past the dead center of the toggle. Thecritical temperature at which the thermostat will operate to effectmovement of the valve operating rod 21 is adjusted by means of the thumbscrew 30, in

accordance with the calibration thereof or the u indications of thepressure gauge 24, whereas the difference between the actuating andrestoring temperatures of the thermostat mechanism is mechanism isadapted to engage the valve opcrating plunger 41 which is slidablymounted in the insulating disk I5 upon an increase in the temperature towhich the capsule 23 is subjected which causes an increase in thepressure upon the piston 25 of the thermostat. The plunger 41 isoperatively connected to a lever 48 pivoted at 49 within the valvehousing I! andhaving depending arms 50 engaging the head 5| of theexpansion valve member 52. The valve member 52 is slidably supported inthe valve housing and is normally biased to a closed position against 52and 53 and adapted to be connected to the condenser or other source ofrefrigerant. The interior of the valve housing is connected through apipe connection 55 to the refrigerating element or expansion coil withwhich the capsule 23 is associated. Inspection of Fig. 1 of the drawingsdiscloses that the internal diameter of the pipe 55, connecting theexpansion valve housing with the refrigerating element or expansioncoil, is substantially the same as the internal diameter of theexpansion valve orifice which adjoins the valve seat 53. This specialdesignretards premature expansion of the refrigerant medium; that is, itretards expansion of the refrigerant medium prior to its reaching therefrigerating element or expansion cofl. This arrangement also makes forthe elimination of frosting about the valve housing and permitsinstallation of the entire evaporator assembly on the exterior ofthecabinet to be refrigerated. The valve housing I9 is sealed at the topby a flexible diaphragm 58 clamped underneath the insulating disk l5.

It will be apparent that upon an increase in the temperature to whichthe capsule 23 is subjected, a pressure is built up in the thermostaticelement and the piston 25 is actuated thereby to throw the toggle 35,31, 38 to the position shown in dotted lines in Fig. 1 and open theexpansion valve 52, 53 to admit refrigerant to the cooling coil. As thetemperature of the cooling coil is lowered, the pressure in the capsule23 decreases and at a predetermined temperature, the spring 28 restoresthe operating rod 21 to its initial position, thereby permitting theexpansion valve to be closed by the spring 56 cut off the supply ofrefrigerant.

As shown in Fig. 2, the details of construction of the thermostaticmechanism may be varied without departing from the scope of theinvention. In the construction shown in Fig.2, the bellows member 23 isreplaced by an equivalent pressure-responsive construction. In thismodification the thermostatic mechanism comprises a housing formed bythe cap members 50 and 5|. A diaphragm 62 corresponding to-the bellowsmember 20 of Fig. 1 is clamped between the cap members 50 and 5|. Thespace above the diaphragm 52 is in communication with a capsule locatedin or adjacent the cooling coils through the passage 53 and tube 54. Theoperating rod 55 for the expansion valve is secured to the diaphragm 62by means of the clamping members 66, whereby the rod is actuated inresponse to changes in pressure to which said diaphragm is subjected.The movement of the piston rod 85 is opposed by the spring 31, thetension of which is adjusted as desired by means of adjusting screw 68.The expansion valve which may be similar to that shown in Fig. 1 and thetoggle link snap-acting mechanism may be supported upon the dependingbrackets 69 and I0, corresponding to the the members I4 and I5 in Fig.1.

The snap-acting thermostatic expansion valve described above is designedfor use in multiple refrigerating systems such as that showndiagrammatically in Fig. 3. The system shown in Fig. 3, by way ofexample, comprises a compressor H, a condenser 12, a liquid receiver 13and a plurality of refrigerating elements or expansion coils 14, 14a.and 1421 connected in multiple to the receiver 13. Expansion valves I5,15a and 1512 are connected to control the supply of refrigerant to therespective cooling coils, the expansion valve being of the constructionshown in Fig. 1 or Fig. 2. By regulating. these valves by means of theadjusting elements 30 and 43, the temperatures of the cooling coils maybe separately controlled and maintained between any desired limits,whereby a temperature may be maintained in one refrigerating compartmentat or below 0 F. and in other compartments at the same or differenttemperature, all of the cooling coils being supplied from a singlecompressor unit. Check valves 15, 15a and "b are preferably providedbetween each of the cooling coils 14, 14a. and 14b and the suctionconnection 11 of the compressor II.

In a ystem embodying the invention two or more I rigerators orevaporators may be maintained at separate or individual temperaturesaccording to the requirementsof each refrigerator while all of therefrigerators may be supplied from a single condensing unit orcompressing unit. The snap-acting thermostat control automaticallymaintains the desired temperature in each refrigerator without attentionor supervision and by reason of the particular construction of thesnap-acting mechanism, a positive operation of the expansion valves isinsured at all times.

Various modifications in the specific construction and arrangement ofthe valves shown may occur to those skilled in the art and are deemed tocome within the scope of the invention it valve to open when thetemperature of said 0001- ing unitreaches a predetermined maximum andcause said snap acting valve to close when the temperature reaches apredetermined minimum.

suction lines from each of said evaporators connected with the suctionside of said compressor, one-way valves disposed in said suction linesfor preventing a back and interflow of refrigerant to and between anyand all of the said evaporators by reason of back pressure in thesuction lines, and as and for the purpose de scribed said expansionvalves constituting the sole expansion means between the condenser andeach of the evaporators.

2. A refrigeration system comprising a compressor-condenser unit, aplurality of cooling units, a liquid line having connections forsupplying refrigerant from the compressor-condenser unit to each of thecooling units, a. return line to the compressor-condenser unit havingconnections with each of the cooling units,

a snap acting expansion valve in the supply lines to each of saidcooling units for independently controlling the supply of refrigerant toeach cool ing unit, said each snap' acting valve being adapted,constructed, and arranged to open in response to a predetermined hightemperature and close in response to a predetermined low temperature,and a check valve in the suction line leading from each cooling unit forpreventing return of refrigerant into the respective cooling units fromthe suction line and thereby equalizing or otherwise afiecting thetemperature of the cooling units said expansion valves constituting thesole expansion means between the condenser and each of the evaporators'.

. WALTER GIIBERQT, SR.

